Class: Rails::Application

Inherits:
Engine show all
Defined in:
railties/lib/rails/application.rb,
railties/lib/rails/application/finisher.rb,
railties/lib/rails/application/bootstrap.rb,
railties/lib/rails/application/configuration.rb,
railties/lib/rails/application/routes_reloader.rb,
railties/lib/rails/application/default_middleware_stack.rb

Overview

An Engine with the responsibility of coordinating the whole boot process.

Initialization

Rails::Application is responsible for executing all railties and engines initializers. It also executes some bootstrap initializers (check Rails::Application::Bootstrap) and finishing initializers, after all the others are executed (check Rails::Application::Finisher).

Configuration

Besides providing the same configuration as Rails::Engine and Rails::Railtie, the application object has several specific configurations, for example enable_reloading, consider_all_requests_local, filter_parameters, logger, and so forth.

Check Rails::Application::Configuration to see them all.

Routes

The application object is also responsible for holding the routes and reloading routes whenever the files change in development.

Middlewares

The Application is also responsible for building the middleware stack.

Booting process

The application is also responsible for setting up and executing the booting process. From the moment you require config/application.rb in your app, the booting process goes like this:

  1. require "config/boot.rb" to set up load paths.

  2. require railties and engines.

  3. Define Rails.application as class MyApp::Application < Rails::Application.

  4. Run config.before_configuration callbacks.

  5. Load config/environments/ENV.rb.

  6. Run config.before_initialize callbacks.

  7. Run Railtie#initializer defined by railties, engines, and application. One by one, each engine sets up its load paths and routes, and runs its config/initializers/* files.

  8. Custom Railtie#initializers added by railties, engines, and applications are executed.

  9. Build the middleware stack and run to_prepare callbacks.

  10. Run config.before_eager_load and eager_load! if eager_load is true.

  11. Run config.after_initialize callbacks.

Defined Under Namespace

Modules: Bootstrap, Finisher Classes: Configuration, DefaultMiddlewareStack, RoutesReloader

Constant Summary collapse

INITIAL_VARIABLES = 
[:config, :railties, :routes_reloader, :reloaders,
:routes, :helpers, :app_env_config]

Constants included from ActiveSupport::Callbacks

ActiveSupport::Callbacks::CALLBACK_FILTER_TYPES

Constants inherited from Railtie

Railtie::ABSTRACT_RAILTIES

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from Engine

#app, #call, endpoint, #endpoint, find, #helpers, isolate_namespace, #load_console, #load_runner, #load_seed, #load_server, #load_tasks, #railties, #routes, #routes?

Methods included from ActiveSupport::Callbacks

#run_callbacks

Methods included from ActiveSupport::Concern

#append_features, #class_methods, extended, #included, #prepend_features, #prepended

Methods inherited from Railtie

<=>, abstract_railtie?, #configure, configure, console, generators, #inspect, railtie_name, #railtie_namespace, rake_tasks, runner, server, subclasses

Methods included from ActiveSupport::DescendantsTracker

clear, #descendants, descendants, disable_clear!, reject!, subclasses

Methods included from Initializable

included, #run_initializers

Constructor Details

#initialize(initial_variable_values = {}, &block) ⇒ Application

Returns a new instance of Application.



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# File 'railties/lib/rails/application.rb', line 107

def initialize(initial_variable_values = {}, &block)
  super()
  @initialized       = false
  @reloaders         = []
  @routes_reloader   = nil
  @app_env_config    = nil
  @ordered_railties  = nil
  @railties          = nil
  @key_generators    = {}
  @message_verifiers = nil
  @deprecators       = nil
  @ran_load_hooks    = false

  @executor          = Class.new(ActiveSupport::Executor)
  @reloader          = Class.new(ActiveSupport::Reloader)
  @reloader.executor = @executor

  @autoloaders = Rails::Autoloaders.new

  # are these actually used?
  @initial_variable_values = initial_variable_values
  @block = block
end

Instance Attribute Details

#assets ⇒ Object

Returns the value of attribute assets.



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# File 'railties/lib/rails/application.rb', line 98

def assets
  @assets
end

#autoloaders ⇒ Object (readonly)

Returns the value of attribute autoloaders.



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# File 'railties/lib/rails/application.rb', line 100

def autoloaders
  @autoloaders
end

#config ⇒ Object

:nodoc:



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# File 'railties/lib/rails/application.rb', line 453

def config # :nodoc:
  @config ||= Application::Configuration.new(self.class.find_root(self.class.called_from))
end

#credentials ⇒ Object

Returns an ActiveSupport::EncryptedConfiguration instance for the credentials file specified by config.credentials.content_path.

By default, config.credentials.content_path will point to either config/credentials/#{environment}.yml.enc for the current environment (for example, config/credentials/production.yml.enc for the production environment), or config/credentials.yml.enc if that file does not exist.

The encryption key is taken from either ENV["RAILS_MASTER_KEY"], or from the file specified by config.credentials.key_path. By default, config.credentials.key_path will point to either config/credentials/#{environment}.key for the current environment, or config/master.key if that file does not exist.



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# File 'railties/lib/rails/application.rb', line 497

def credentials
  @credentials ||= encrypted(config.credentials.content_path, key_path: config.credentials.key_path)
end

#executor ⇒ Object (readonly)

Returns the value of attribute executor.



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# File 'railties/lib/rails/application.rb', line 100

def executor
  @executor
end

#reloader ⇒ Object (readonly)

Returns the value of attribute reloader.



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# File 'railties/lib/rails/application.rb', line 100

def reloader
  @reloader
end

#reloaders ⇒ Object (readonly)

Returns the value of attribute reloaders.



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# File 'railties/lib/rails/application.rb', line 100

def reloaders
  @reloaders
end

#sandbox ⇒ Object Also known as: sandbox?

Returns the value of attribute sandbox.



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# File 'railties/lib/rails/application.rb', line 98

def sandbox
  @sandbox
end

Class Method Details

.add_lib_to_load_path!(root) ⇒ Object

This method is called just after an application inherits from Rails::Application, allowing the developer to load classes in lib and use them during application configuration.

class MyApplication < Rails::Application
  require "my_backend" # in lib/my_backend
  config.i18n.backend = MyBackend
end

Notice this method takes into consideration the default root path. So if you are changing config.root inside your application definition or having a custom Rails application, you will need to add lib to $LOAD_PATH on your own in case you need to load files in lib/ during the application configuration as well.



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# File 'railties/lib/rails/application.rb', line 409

def self.add_lib_to_load_path!(root) # :nodoc:
  path = File.join(root, "lib")
  if File.exist?(path) && !$LOAD_PATH.include?(path)
    $LOAD_PATH.unshift(path)
  end
end

.create(initial_variable_values = {}, &block) ⇒ Object 



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# File 'railties/lib/rails/application.rb', line 82

def create(initial_variable_values = {}, &block)
  new(initial_variable_values, &block).run_load_hooks!
end

.find_root(from) ⇒ Object 



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# File 'railties/lib/rails/application.rb', line 86

def find_root(from)
  find_root_with_flag "config.ru", from, Dir.pwd
end

.inherited(base) ⇒ Object 



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# File 'railties/lib/rails/application.rb', line 69

def inherited(base)
  super
  Rails.app_class = base
  # lib has to be added to $LOAD_PATH unconditionally, even if it's in the
  # autoload paths and config.add_autoload_paths_to_load_path is false.
  add_lib_to_load_path!(find_root(base.called_from))
  ActiveSupport.run_load_hooks(:before_configuration, base)
end

.instance ⇒ Object 



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# File 'railties/lib/rails/application.rb', line 78

def instance
  super.run_load_hooks!
end

Instance Method Details

#config_for(name, env: Rails.env) ⇒ Object

Convenience for loading config/foo.yml for the current Rails env. Example:

# config/exception_notification.yml:
production:
  url: http://127.0.0.1:8080
  namespace: my_app_production

development:
  url: http://localhost:3001
  namespace: my_app_development


# config/environments/production.rb
Rails.application.configure do
  config.middleware.use ExceptionNotifier, config_for(:exception_notification)
end

You can also store configurations in a shared section which will be merged with the environment configuration

# config/example.yml
shared:
  foo:
    bar:
      baz: 1

development:
  foo:
    bar:
      qux: 2


# development environment
Rails.application.config_for(:example)[:foo][:bar]
# => { baz: 1, qux: 2 }



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# File 'railties/lib/rails/application.rb', line 290

def config_for(name, env: Rails.env)
  yaml = name.is_a?(Pathname) ? name : Pathname.new("#{paths["config"].existent.first}/#{name}.yml")

  if yaml.exist?
    require "erb"
    all_configs    = ActiveSupport::ConfigurationFile.parse(yaml).deep_symbolize_keys
    config, shared = all_configs[env.to_sym], all_configs[:shared]

    if shared
      config = {} if config.nil? && shared.is_a?(Hash)
      if config.is_a?(Hash) && shared.is_a?(Hash)
        config = shared.deep_merge(config)
      elsif config.nil?
        config = shared
      end
    end

    if config.is_a?(Hash)
      config = ActiveSupport::OrderedOptions.new.update(config)
    end

    config
  else
    raise "Could not load configuration. No such file - #{yaml}"
  end
end

#console(&blk) ⇒ Object

Sends any console called in the instance of a new application up to the console method defined in Rails::Railtie.



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# File 'railties/lib/rails/application.rb', line 373

def console(&blk)
  self.class.console(&blk)
end

#deprecators ⇒ Object

A managed collection of deprecators (ActiveSupport::Deprecation::Deprecators). The collection’s configuration methods affect all deprecators in the collection. Additionally, the collection’s silence method silences all deprecators in the collection for the duration of a given block.



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# File 'railties/lib/rails/application.rb', line 246

def deprecators
  @deprecators ||= ActiveSupport::Deprecation::Deprecators.new.tap do |deprecators|
    deprecators[:railties] = Rails.deprecator
  end
end

#eager_load! ⇒ Object

Eager loads the application code.



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# File 'railties/lib/rails/application.rb', line 555

def eager_load!
  Rails.autoloaders.each(&:eager_load)
end

#encrypted(path, key_path: "config/master.key", env_key: "RAILS_MASTER_KEY") ⇒ Object

Returns an ActiveSupport::EncryptedConfiguration instance for an encrypted file. By default, the encryption key is taken from either ENV["RAILS_MASTER_KEY"], or from the config/master.key file.

my_config = Rails.application.encrypted("config/my_config.enc")

my_config.read
# => "foo:\n  bar: 123\n"

my_config.foo.bar
# => 123

Encrypted files can be edited with the bin/rails encrypted:edit command. (See the output of bin/rails encrypted:edit --help for more information.)



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# File 'railties/lib/rails/application.rb', line 516

def encrypted(path, key_path: "config/master.key", env_key: "RAILS_MASTER_KEY")
  ActiveSupport::EncryptedConfiguration.new(
    config_path: Rails.root.join(path),
    key_path: Rails.root.join(key_path),
    env_key: env_key,
    raise_if_missing_key: config.require_master_key
  )
end

#env_config ⇒ Object

Stores some of the Rails initial environment parameters which will be used by middlewares and engines to configure themselves.



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# File 'railties/lib/rails/application.rb', line 319

def env_config
  @app_env_config ||= super.merge(
      "action_dispatch.parameter_filter" => filter_parameters,
      "action_dispatch.redirect_filter" => config.filter_redirect,
      "action_dispatch.secret_key_base" => secret_key_base,
      "action_dispatch.show_exceptions" => config.action_dispatch.show_exceptions,
      "action_dispatch.show_detailed_exceptions" => config.consider_all_requests_local,
      "action_dispatch.log_rescued_responses" => config.action_dispatch.log_rescued_responses,
      "action_dispatch.debug_exception_log_level" => ActiveSupport::Logger.const_get(config.action_dispatch.debug_exception_log_level.to_s.upcase),
      "action_dispatch.logger" => Rails.logger,
      "action_dispatch.backtrace_cleaner" => Rails.backtrace_cleaner,
      "action_dispatch.key_generator" => key_generator,
      "action_dispatch.http_auth_salt" => config.action_dispatch.http_auth_salt,
      "action_dispatch.signed_cookie_salt" => config.action_dispatch.signed_cookie_salt,
      "action_dispatch.encrypted_cookie_salt" => config.action_dispatch.encrypted_cookie_salt,
      "action_dispatch.encrypted_signed_cookie_salt" => config.action_dispatch.encrypted_signed_cookie_salt,
      "action_dispatch.authenticated_encrypted_cookie_salt" => config.action_dispatch.authenticated_encrypted_cookie_salt,
      "action_dispatch.use_authenticated_cookie_encryption" => config.action_dispatch.use_authenticated_cookie_encryption,
      "action_dispatch.encrypted_cookie_cipher" => config.action_dispatch.encrypted_cookie_cipher,
      "action_dispatch.signed_cookie_digest" => config.action_dispatch.signed_cookie_digest,
      "action_dispatch.cookies_serializer" => config.action_dispatch.cookies_serializer,
      "action_dispatch.cookies_digest" => config.action_dispatch.cookies_digest,
      "action_dispatch.cookies_rotations" => config.action_dispatch.cookies_rotations,
      "action_dispatch.cookies_same_site_protection" => coerce_same_site_protection(config.action_dispatch.cookies_same_site_protection),
      "action_dispatch.use_cookies_with_metadata" => config.action_dispatch.use_cookies_with_metadata,
      "action_dispatch.content_security_policy" => config.content_security_policy,
      "action_dispatch.content_security_policy_report_only" => config.content_security_policy_report_only,
      "action_dispatch.content_security_policy_nonce_generator" => config.content_security_policy_nonce_generator,
      "action_dispatch.content_security_policy_nonce_directives" => config.content_security_policy_nonce_directives,
      "action_dispatch.permissions_policy" => config.permissions_policy,
    )
end

#generators(&blk) ⇒ Object

Sends any generators called in the instance of a new application up to the generators method defined in Rails::Railtie.



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# File 'railties/lib/rails/application.rb', line 379

def generators(&blk)
  self.class.generators(&blk)
end

#helpers_paths ⇒ Object

:nodoc:



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# File 'railties/lib/rails/application.rb', line 529

def helpers_paths # :nodoc:
  config.helpers_paths
end

#initialize!(group = :default) ⇒ Object

Initialize the application passing the given group. By default, the group is :default



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# File 'railties/lib/rails/application.rb', line 440

def initialize!(group = :default) # :nodoc:
  raise "Application has been already initialized." if @initialized
  run_initializers(group, self)
  @initialized = true
  self
end

#initialized? ⇒ Boolean

Returns true if the application is initialized.

Returns:

  • (Boolean) 


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# File 'railties/lib/rails/application.rb', line 132

def initialized?
  @initialized
end

#initializer(name, opts = {}, &block) ⇒ Object

Sends the initializers to the initializer method defined in the Rails::Initializable module. Each Rails::Application class has its own set of initializers, as defined by the Initializable module.



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# File 'railties/lib/rails/application.rb', line 361

def initializer(name, opts = {}, &block)
  self.class.initializer(name, opts, &block)
end

#initializers ⇒ Object

:nodoc:



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# File 'railties/lib/rails/application.rb', line 447

def initializers # :nodoc:
  Bootstrap.initializers_for(self) +
  railties_initializers(super) +
  Finisher.initializers_for(self)
end

#isolate_namespace(mod) ⇒ Object

Sends the isolate_namespace method up to the class method.



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# File 'railties/lib/rails/application.rb', line 390

def isolate_namespace(mod)
  self.class.isolate_namespace(mod)
end

#key_generator(secret_key_base = self.secret_key_base) ⇒ Object

Returns a key generator (ActiveSupport::CachingKeyGenerator) for a specified secret_key_base. The return value is memoized, so additional calls with the same secret_key_base will return the same key generator instance.



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# File 'railties/lib/rails/application.rb', line 174

def key_generator(secret_key_base = self.secret_key_base)
  # number of iterations selected based on consultation with the google security
  # team. Details at https://github.com/rails/rails/pull/6952#issuecomment-7661220
  @key_generators[secret_key_base] ||= ActiveSupport::CachingKeyGenerator.new(
    ActiveSupport::KeyGenerator.new(secret_key_base, iterations: 1000)
  )
end

#load_generators(app = self) ⇒ Object

:nodoc:



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# File 'railties/lib/rails/application.rb', line 549

def load_generators(app = self) # :nodoc:
  app.ensure_generator_templates_added
  super
end

#message_verifier(verifier_name) ⇒ Object

Returns a message verifier object.

This verifier can be used to generate and verify signed messages in the application.

It is recommended not to use the same verifier for different things, so you can get different verifiers passing the verifier_name argument.

For instance, ActiveStorage::Blob.signed_id_verifier is implemented using this feature, which assures that the IDs strings haven’t been tampered with and are safe to use in a finder.

See the ActiveSupport::MessageVerifier documentation for more information.

Parameters

  • verifier_name - the name of the message verifier.

Examples

message = Rails.application.message_verifier('my_purpose').generate('data to sign against tampering')
Rails.application.message_verifier('my_purpose').verify(message)
# => 'data to sign against tampering'



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# File 'railties/lib/rails/application.rb', line 238

def message_verifier(verifier_name)
  message_verifiers[verifier_name]
end

#message_verifiers ⇒ Object

Returns a message verifier factory (ActiveSupport::MessageVerifiers). This factory can be used as a central point to configure and create message verifiers (ActiveSupport::MessageVerifier) for your application.

By default, message verifiers created by this factory will generate messages using the default ActiveSupport::MessageVerifier options. You can override these options with a combination of ActiveSupport::MessageVerifiers#clear_rotations and ActiveSupport::MessageVerifiers#rotate. However, this must be done prior to building any message verifier instances. For example, in a before_initialize block:

# Use `url_safe: true` when generating messages
config.before_initialize do |app|
  app.message_verifiers.clear_rotations
  app.message_verifiers.rotate(url_safe: true)
end

Message verifiers created by this factory will always use a secret derived from #secret_key_base when generating messages. clear_rotations will not affect this behavior. However, older secret_key_base values can be rotated for verifying messages:

# Fall back to old `secret_key_base` when verifying messages
config.before_initialize do |app|
  app.message_verifiers.rotate(secret_key_base: "old secret_key_base")
end



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# File 'railties/lib/rails/application.rb', line 210

def message_verifiers
  @message_verifiers ||=
    ActiveSupport::MessageVerifiers.new do |salt, secret_key_base: self.secret_key_base|
      key_generator(secret_key_base).generate_key(salt)
    end.rotate_defaults
end

#migration_railties ⇒ Object

Return an array of railties respecting the order they’re loaded and the order specified by the railties_order config.

While running initializers we need engines in reverse order here when copying migrations from railties ; we need them in the order given by railties_order.



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# File 'railties/lib/rails/application.rb', line 545

def migration_railties # :nodoc:
  ordered_railties.flatten - [self]
end

#name ⇒ Object

Returns the dasherized application name.

MyApp::Application.new.name => "my-app"



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# File 'railties/lib/rails/application.rb', line 139

def name
  self.class.name.underscore.dasherize.delete_suffix("/application")
end

#rake_tasks(&block) ⇒ Object

If you try to define a set of Rake tasks on the instance, these will get passed up to the Rake tasks defined on the application’s class.



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# File 'railties/lib/rails/application.rb', line 354

def rake_tasks(&block)
  self.class.rake_tasks(&block)
end

#reload_routes! ⇒ Object

Reload application routes regardless if they changed or not.



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# File 'railties/lib/rails/application.rb', line 158

def reload_routes!
  if routes_reloader.execute_unless_loaded
    routes_reloader.loaded = false
  else
    routes_reloader.reload!
  end
end

#reload_routes_unless_loaded ⇒ Object

:nodoc:



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# File 'railties/lib/rails/application.rb', line 166

def reload_routes_unless_loaded # :nodoc:
  initialized? && routes_reloader.execute_unless_loaded
end

#require_environment! ⇒ Object

:nodoc:



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# File 'railties/lib/rails/application.rb', line 416

def require_environment! # :nodoc:
  environment = paths["config/environment"].existent.first
  require environment if environment
end

#routes_reloader ⇒ Object

:nodoc:



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# File 'railties/lib/rails/application.rb', line 421

def routes_reloader # :nodoc:
  @routes_reloader ||= RoutesReloader.new
end

#run_load_hooks! ⇒ Object

:nodoc:



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# File 'railties/lib/rails/application.rb', line 143

def run_load_hooks! # :nodoc:
  return self if @ran_load_hooks
  @ran_load_hooks = true

  @initial_variable_values.each do |variable_name, value|
    if INITIAL_VARIABLES.include?(variable_name)
      instance_variable_set("@#{variable_name}", value)
    end
  end

  instance_eval(&@block) if @block
  self
end

#runner(&blk) ⇒ Object

Sends any runner called in the instance of a new application up to the runner method defined in Rails::Railtie.



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# File 'railties/lib/rails/application.rb', line 367

def runner(&blk)
  self.class.runner(&blk)
end

#secret_key_base ⇒ Object

The secret_key_base is used as the input secret to the application’s key generator, which in turn is used to create all ActiveSupport::MessageVerifier and ActiveSupport::MessageEncryptor instances, including the ones that sign and encrypt cookies.

We look for it first in ENV["SECRET_KEY_BASE"], then in credentials.secret_key_base. For most applications, the correct place to store it is in the encrypted credentials file.

In development and test, if the secret_key_base is still empty, it is randomly generated and stored in a temporary file in tmp/local_secret.txt.

Generating a random secret_key_base and storing it in tmp/local_secret.txt can also be triggered by setting ENV["SECRET_KEY_BASE_DUMMY"]. This is useful when precompiling assets for production as part of a build step that otherwise does not need access to the production secrets.

Dockerfile example: RUN SECRET_KEY_BASE_DUMMY=1 bundle exec rails assets:precompile.



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# File 'railties/lib/rails/application.rb', line 479

def secret_key_base
  config.secret_key_base
end

#server(&blk) ⇒ Object

Sends any server called in the instance of a new application up to the server method defined in Rails::Railtie.



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# File 'railties/lib/rails/application.rb', line 385

def server(&blk)
  self.class.server(&blk)
end

#to_app ⇒ Object

:nodoc:



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# File 'railties/lib/rails/application.rb', line 525

def to_app # :nodoc:
  self
end

#watchable_args ⇒ Object

Returns an array of file paths appended with a hash of directories-extensions suitable for ActiveSupport::FileUpdateChecker API.



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# File 'railties/lib/rails/application.rb', line 428

def watchable_args # :nodoc:
  files, dirs = config.watchable_files.dup, config.watchable_dirs.dup

  Rails.autoloaders.main.dirs.each do |path|
    dirs[path] = [:rb]
  end

  [files, dirs]
end